1. Field of the Invention
The present invention relates to internal combustion engine controls and, more particularly, to a device for shutting off an internal combustion engine by inhibiting the ignition current. The device is instantaneously operable and resets itself automatically to a non-inhibiting condition when the engine is no longer running, so that the engine may be restarted without manually resetting the shut-off device.
2. Description of the Prior Art
Many vehicles, such as snowmobiles, motorcycles and minibikes, and many types of mechanical equipment, such as lawnmowers, outboard motors, snowblowers and portable generators, are powered by internal combustion engines. When the operator of such a vehicle or machine wishes to shut off the engine, he usually activates a shut-off control which inhibits delivery of ignition current to the spark coil or spark plugs. Thus, while fuel may still be fed into the combustion chamber, it is not ignited, and the motor soon dies. Shut-off controls conventionally used are basically of two types. In one type, a switch is manually activated which grounds or otherwise interrupts or inhibits the ignition circuit, effectively killing the engine without further operator attention. In the second type, the shut-off switch also inhibits the ignition circuit, but the switch must be attended to until the operator is sure the engine has died.
The first type of shut-off switch has the disadvantage that it must typically be reset before the engine can be restarted. Should the operator neglect to do this, he may flood the engine before he realizes his error and restores the ignition system to its non-inhibited state. In addition, when the vehicle or machine is operated in the dark it is difficult to tell whether the "push-push" or slide type shut-off switches conventionally used to control the device have been reset for starting or not. If the state of the switch is not properly determined before restarting, flooding the engine is again possible.
With the second type of shut-off switch, resetting of the switch before the next start is typically unnecessary because the switch has no ignition-inhibiting effect when the operator ceases tending it. However, continued operator attention is usually required until the engine fully dies. This makes it difficult or impossible to shut off the engine quickly in emergency situations where the operator is forced to leave the vehicle or machine.